In regular CMM, the terrain geomorphology is not taken into account therefore, it is preferable to use them for flat terrain. If there are large-scale maps and plans for a site, then they create a DTM in the form of an array of points located at certain intervals on the horizontal lines by moving the digitizer reticle horizontally (Fig. Also use regular CMM at diameters to the main course (Fig. The digital terrain model in which the reference points with known coordinates are located at the nodes of geometric grids of various shapes, for example, in the form of a network of squares or equilateral triangles (Fig. Classification of digital terrain modelsĬlassification of CMM by purpose corresponds to the general classification of maps: topographic, contour, geological, cadastral, etc.Īccording to the method of placing the initial information and the rules of its processing on a computer, digital terrain models are divided into regular, irregular, structural (Fig. The initial data for creating digital terrain models are the results of topographic surveys, data on the geology and hydrography of the terrain.Ĥ.2. Computer-aided design based on CMM and MMM reduces labor and time costs by tens of times compared to using paper topographic maps and plans for this purpose. When solving engineering and geodetic problems on a computer, a mathematical interpretation of digital models is used, it is called a mathematical terrain model (MMM). In engineering practice, a combination of digital models characterizing the situation, topography, hydrological, geotechnical, feasibility and other indicators are often used.ĭTMs are created using special computer-aided design (CAD) modules such as AutoCad Land Development Desktop, Autodesk Civil 3D, Autodesk Map 3D, Pythagoras, Credo, GeoniCS, Topomatic Robur, and others In addition, CMM can be supplemented by a model of special engineering purposes (CMIN). It consists of a digital terrain model (DEMR) and a digital contour model (situation) for the terrain (MSCM). Topographic CMM characterizes the situation and the terrain. General information - the name of the site, the system of coordinates and heights, the nomenclature. Structural information describing the relationship between different objects - the relationship of objects to any set: separate points of the railway line, buildings and structures of the settlement, the structure and structure of the relevant industries, etc. Semantic information characterizing the properties of objects - technical parameters of engineering structures, geological characteristics of soils, data on trees in forests, etc. Syntactic information for describing connections between points - the boundaries of buildings, forests, arable lands, reservoirs, roads, watersheds and spillways, the direction of the slopes between characteristic points on the slopes, etc. Metric information - geodetic spatial coordinates of characteristic points of relief and situation In accordance with this standard, a digital terrain model (DTM) is a logical-mathematical representation in digital form of topographic and geodetic data about terrain objects and its characteristics. The terms and definitions of concepts in the field of digital mapping, as well as the use of digital and electronic maps and models are established by the interstate standard GOST 28441-99 “Digital cartography.